CA1068103A - Method of drying a cardboard or a paper web and drying device for applying this method - Google Patents
Method of drying a cardboard or a paper web and drying device for applying this methodInfo
- Publication number
- CA1068103A CA1068103A CA267,393A CA267393A CA1068103A CA 1068103 A CA1068103 A CA 1068103A CA 267393 A CA267393 A CA 267393A CA 1068103 A CA1068103 A CA 1068103A
- Authority
- CA
- Canada
- Prior art keywords
- band
- drying
- web
- cooling
- water
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- D—TEXTILES; PAPER
- D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
- D21F—PAPER-MAKING MACHINES; METHODS OF PRODUCING PAPER THEREON
- D21F5/00—Dryer section of machines for making continuous webs of paper
- D21F5/004—Drying webs by contact with heated surfaces or materials
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F26—DRYING
- F26B—DRYING SOLID MATERIALS OR OBJECTS BY REMOVING LIQUID THEREFROM
- F26B13/00—Machines and apparatus for drying fabrics, fibres, yarns, or other materials in long lengths, with progressive movement
- F26B13/10—Arrangements for feeding, heating or supporting materials; Controlling movement, tension or position of materials
- F26B13/105—Drying webs by contact with heated surfaces other than rollers or drums
Landscapes
- Engineering & Computer Science (AREA)
- Textile Engineering (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Drying Of Solid Materials (AREA)
- Paper (AREA)
Abstract
A Method of Drying a Cardboard or a Paper Web and Drying Device for Applying this Method.
Abstract of the Disclosure.
A method of drying a cardboard or a paper web by passing the wet web supported by a drying band between two moving, nonpermeable surface elements having good heat conducting properties. The surface element contacting the web is subjected to heating and the surface element contacting the drying band is subjected to cooling. Due to the heating of the web the water contained there in is caused to evaporate and the evaporated water is caused to condense into the drying band due to the cooling of the drying band. The water is removed from the drying band after the web and the drying hand have left the surface elements and have been separated from each other.
Abstract of the Disclosure.
A method of drying a cardboard or a paper web by passing the wet web supported by a drying band between two moving, nonpermeable surface elements having good heat conducting properties. The surface element contacting the web is subjected to heating and the surface element contacting the drying band is subjected to cooling. Due to the heating of the web the water contained there in is caused to evaporate and the evaporated water is caused to condense into the drying band due to the cooling of the drying band. The water is removed from the drying band after the web and the drying hand have left the surface elements and have been separated from each other.
Description
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,. c ~
106~3103 Thls inventTon relates to a method of drying a cardboard or a paper web by passing the web supported by a drying band into contact with a heated drying surface --tn order to evaporate water from the web.
Cardboard and paper drylng is carried out today malnly by means of cylinder dryers comprising several rotating cylTnders which are internally heated with steam and agalnst the surfaces of which the web is pressed by means of a felt or a drying wlre. Thcre are however dlsadvantages In thls drytng method: the big slze of the dry1ng device the high purchase price the high cperating costs the operating stoppages caused by frequent web breaks as well as the dangerous sltuatlons arislng from the breaks.
To some extent alr-float dryers are also used In . . .
whlch the web Is supported horlzontally by a zone of hot alr 3ets. The process results in a web wlth a less smooth surface than that produced wlth cylInder dryers and the drylng costs are hlgher than when using cylinder dryers.
Infrared-dryers are also used in which heat radlatTon Is generated either by means of electric resistance wlres or by burnlng gas. Devices of thls type are mostly used only as auxlllary dryers.
The ob3ect of thls invention Is to provTde a drylng method which in many respects Is more advantageous than the presently used dry1ng methods. This object is reached by a method ~n accordance with the inventlon the characterlst~cs of which are that the wet web and the drying band are passed between two moving nonpermcable - 30 surface elements having good heat conducting properties .
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106~3103 Thls inventTon relates to a method of drying a cardboard or a paper web by passing the web supported by a drying band into contact with a heated drying surface --tn order to evaporate water from the web.
Cardboard and paper drylng is carried out today malnly by means of cylinder dryers comprising several rotating cylTnders which are internally heated with steam and agalnst the surfaces of which the web is pressed by means of a felt or a drying wlre. Thcre are however dlsadvantages In thls drytng method: the big slze of the dry1ng device the high purchase price the high cperating costs the operating stoppages caused by frequent web breaks as well as the dangerous sltuatlons arislng from the breaks.
To some extent alr-float dryers are also used In . . .
whlch the web Is supported horlzontally by a zone of hot alr 3ets. The process results in a web wlth a less smooth surface than that produced wlth cylInder dryers and the drylng costs are hlgher than when using cylinder dryers.
Infrared-dryers are also used in which heat radlatTon Is generated either by means of electric resistance wlres or by burnlng gas. Devices of thls type are mostly used only as auxlllary dryers.
The ob3ect of thls invention Is to provTde a drylng method which in many respects Is more advantageous than the presently used dry1ng methods. This object is reached by a method ~n accordance with the inventlon the characterlst~cs of which are that the wet web and the drying band are passed between two moving nonpermcable - 30 surface elements having good heat conducting properties .
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and which enclose the web along its whole width, that the surface element contacting the web is subjected to heating, and the surface element contacting the drying band is subJected to cool~ng in order to condense water evaporating from the web into the drying band, and that the drying band is separated from the dry web after they left the surface elements, and the condensed water is then removed from the drytng band.
''~ The method in accordance' w7th the invention facilltates the drying of a cardboard or a paper web by uslng the so-called suction drytng principle, the general basis of which is that the liquid or material to be dried Is In contact only with evaporating st.eam. When the pressure of the eavaporating steam is kept low by condensing the steam upon some cold surface, the evaporation takes place at a low temperature and at a low pressure. In ' sptte of the low evaporation temperature the speed of evaporat70n is very high, because the evaporating liquid botls and the heated surface can be several degrees warmer ~ 20 than the liquid itself. The temperature of the liquid thus -' reaches a value between the temperatures of the evaporating surface and the condensing surface. By passing the web to be dried and the drying band between two surface ~; elements, one of which is heated and the other is cooled, the web undergoes such a suction drying in a continuous process by causing the surface elements to run at the same speed as the web and the drying band.
Considerable advantages In suctton drying according to the tnvention are t'he htgh drying speed at a low temperature, the slmplicity of the process and the uni-, . .
formity of the process conditions.
The drying speed decreases sharply if air remains _ _ _ .
.
`` :` 1~68~103 `~
between the surface elements and in the web and/or in thedrying band. In such a case the steam evaporating from the web has to diffuse through a layer of air in order to be able to condense near the cooled surface element.
Thus, air increases the total drying resistance. For ~ -this reason, subjecting the web and the drying band to an air eliminating process before passing them~;~
between the surface elements is an essential part of the method.
The invention relates also to a drying device for applying the method in accordance with the invention.
Advantages of the drying device according to the invention are a very low purchase price and a low cost of energy consumption as well as a moderate cost of maintenance, Furthermore, the drying device is small!
noiseless and safe. The drying method in accordance with the invention does not place any restrictions on the basis weight, the speed or the quality of the web, and passing the web through the dryer as well as quality changes are easy to carry ou~. The drying of the web takes place at - ~
a low temperature so that the quality is good, and web breaks occur rarely.
As a drying band can be used a drying felt having numerous parallel flow canals passing through the felt . i!
perpendicularly to the surfaces thereof. In order to improve dewatering of the web to be dried it is ~ advantageous to use a drying band in which the part facing ;~ the web is more hydrophobic than the part facing the cooled surface element.
When the web is supported by such a drying band, ; it is easier than when using a drying felt to make sure that the surfaces of the drylng band and the cooled . . .
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~68103 surface element, when needed, are such that the steam conden5ed thereon can be removed as easily as possible, whereby at the same time the risk decreases that the water which has evaporated from the web into the drying band would return into the web at some stage of the process.
By making the surface of the drying band facing the web more hydrophobic than the surface facing the cooled surface element the water, whlch has evaporated from the web, is prevented to pass by means of capillarity back Tnto the web even 7f the drying band would run above the web.
In addition to the advantages explained above the use of a drying wire Instead of a drylng felt ~aves both In the purchase price and in the maintenance costs due to longer wire change intervals.
The water resistance of the wire Ts accomplished by treatlng it with some suitable substance or by coating It sultably. It Ts also advantageous that the surface or the wire of the drylng band which faces the cooled surface element Is more water reslstant than satd rooled surface element. In this manner tt ts possible to obtain that elther the dryTng band or the cooled surface element retainS more water when the cooled surface element and the drying band are separated.
In the following the inventton will be described more closely with reference to the accompanytng drawing , in which Flg. 1 Is a schematic slde vtew of one embodtment of a drylng devlce for carrying out the drytng method provTded by the tnvention, Ftg. 2 ts an enlarged sectlon along line 11-11 tn Flg. 1, Fig. 3 ts an enlarged section of the edge part of the bands, and Figures 4-6 are enlarged cross sections of _ _ _ _ .;. .
.:
., . .. ~
i~68~03 embo~iments o~ a drying band havTng surface por~ions with different hydrophobic properties.
The dryer illustrated in the drawing comprises mainly two surface elements 1 an 2 formed by two endless bands, which are of nonpermeable stainless steel or other metal, rubber or plast7c. The surface elements run over ~ .
horlzontal turning rolls 3, so that between those parts of the surface elements which are position&d close to each other remalns essentlally a space with corresponds to the thickneSS of the web and the drying band. An endless drying band 4, in this case a dryTng felt, runs between - the surface elements, passes over the other turning roll 3, and returns by a route below ~he lower surface element, passTng over ordTnary guTde rolls 5. The surface elements are wTder than the web. The cardboard or paper web to be dried Ts indlcated wTth t~e reference numeral 6.
The dryer further comprTses a steam chest 7, whTch is placed above the lower run of the ~pper surface band 1 and Into whTch saturated steam (100C, 1 bar) Ts supplied from a tube 8. The chest Ts further provTded wTth condensate : collectors 9 and outlet tubes 10 for condensed water (100C).
.....
~; A shower chest 11 is posTtToned underneath the upper run of j the lower surface element 2, Tn whTch shower chest there i is a group of tubes 12 for sprayTns cooling water having a temperature of 0-20C UpOIl the lower surface of the surface element. The inlet tube for water Ts indTcat.ed wTth . 13, and the outlet tube for used cooling water is tndicated `~ with 14.
On opposlte sides of the w~b before it passes between the surface elements are located radTant heaters 15, and after the heaters a steam chest 16A into whTch superheated steam (about 120C) Ts supplTed from a tube 17, and a ;; 6 . .. ~ ..
... . , ~.. ... .... ... . .
1~68103 suction box 16B which is subjected to suction by means of a suction tube 18. For drying the drying band there are suction boxes 19.
in the described construction the dryer comprises two drying sections I and 11 in succession, between which drying sections there is a steam space 20, the top and bottom of which are covered, but the sides open. Super-heated steam (about 120C) Is supplied into the steam space - from tubes 21.
The corresponding parts of the drying section 11 are provided with the same reference numerals as in the drying secti~n 1 The drying section 11 is further provlded with an apparatus 22 for regulating the humidity proflle of the web by means of cold water, and the constructlon of the suctlon-steam box 16 differs from that of section 1.
The drylng of the web Is accomplished as follows:
The web Is passed through the radiant heaters 15, ; 20 which burn gas or use electrlcal resistances, whereby the temperature of at least the surfaces of the web rlses up to 100C. The generated steam pushes air out of the web. T;,ereafter the web and the drylng band are passed together over the suctlon box 16B, and at the same time superheated steam from the alr tlght steam box 16A Is blown through the web and the drylng band. The superheated steam pushes the remalnlng alr out of the web and the drytng band After thls the web and the drylng band are not allowed to contact alr before they enter between the . 30 surface elements 1, ~.
The leaklng of air Into the drylng band or the web from the sides of the machlne Is prevented, for Instance by suitable seals 23 at the edges of the drylng band (Flg. 3).
-, . - `~
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-~68103 ; The surface elements 1, 2 move at the same speed as the drying band and the web. While passtng under the steam box 7 the upper surface element 1 is heated by the action of the saturated steam which flows into the chest. The steam condenses on the surface of the upper surface element and the condensate is removed, or it drops off. The latent heat of condensation passes through the upper surface element Into the wet web. The moisture of the web evaporates at a temperature of ~0...90C, whereby the pressure (abs) of the evaporating steam is 0,20... 0,69 bar. This steam passes through the drylng band into the vicinity of the lower surface element 2. By means of cold water spraying the temperature of this surface element Ts kept at about ; lo 40C whtle passing over ~he shower chest 11. Thus the steam evaporated f!om the web condenses correspondtngly ` at a pressure (abs) of 0,01... 0,12 bar. The dryTng flux , becomes extremely hlgh, and tt Ts possTble to reach drylng values which greatly exceed the hlghest values presently achTeved.
Because the dryer consists of several dryTng .
. sections 1, Il, the web separates between the sectTons from t~e dryTng band, and Ts thus able to free Ttself of ,,;. 1 1 Its resldual stresses. Between the drylng sectlons the web ~s prevented from contact wtth aTr by means of the steam space 20. A!ternatTvely, the sheet can be passed from one drylng sectTon to the followTng completely uncovered, and ,~ the air can be removed from the web and the dryTng band sTmultaneously as they enter the second dryTng sectTon.
;
~ . The dryTng band Ts drTed by one or more of the r;~ 30 presently used methods, e.g. by passTng tt over suctlon i ,' .
. ,~ .
:. . . . ....
-: ~ ,, . ; . . ..... ... , , .: .. . . .
boxes lg, and by blowing slmultaneously superheated steam through the band. The drying band must be of a type that has numerous parallel flow canals passing through the drying band perpendicularly to the surfaces thereof, but hardly allows any gas flow in the machTne direction or the cross machine direction.
W7th this dryer tt is a very easy and safe procedure to pass the front end of the web through the dryer. A
support rope can also be used between the drying sections.
The air eliminating process and ~he drying of the drying bands causes an air-steam mixture, the temperature ; of which is about 100C. The enthalpy of this can be uttlized in the same way as the enthalpy of the humid air resulting from the hood of a normal dryer is being used at present.
Figures 4-6 711ustrate alternat7ve embodiments of a drytng band having surface portions with different hydrophobic properttes The drying band 4A, fig. 4,can consist of one paper machlne wlre, in whlch the surface 4a faclng the web 6 is more h~drophobic than the surface facing the cooled surface element. The wlre has to be of a texture fine enough not to ; leave harmful marks In the web, and thick enough to hold easlly all the water leavtng the web. The wire can be either of metal or plastlcs It Is also possible that the drylng band 4B, flg. 5, conslsts of two wlres placed one on top of the other, whereby , the wire 4c faclng the web 6 Is of flne texture and hydrophobic, and the wlre 4d faclng the cooled surface element 2 Is coarse and less hydrophoblc than the wire facing the web. The wlre 4c faclng the web has to be of ` a texture fine enough to avoid marks In the web, and the o~ther wtre 4d, whlch collects the condensate, has to be spac70us enough to receive all the water coming from the web. The wlres can be either of metal or plast1cs.
. ,.
. . . --- ~ , , : ~ . . . . ., . :.
lQ68~03 Alternatively, the drying band 4C, fig~ 6,can consist of three wires laid one on top of the other, whereby the wire 4e facing the web 6 is of fine texture, the wire 4f in the middle is hydrophobic, and the wire 4a facing the cooled surface element 2 is less hydrophobic than the wire in the middle. The wire 4e facing the web has agatn to be of a texture fine enough in order not to cause markings in the web. The wTre 4f in the middle has to be intens~vely hydrophobTc, and the wire 4g which is located most distant from the web and collects the condensate has to be less hydrophobic and spacious enough to receive easlly all the water coming from the web. The wlre 1n the middle 7s advantageously of plastics only. The two other wtres can be either of metal or plastics.
The drawing and the associated description are alnled only at 111ustrating the basic idea tnvolved with the Inventlon. The details of the embodiments for carry;ng out the method accordtng to the invention may vary considerably withln the scope o~ the claims.
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and which enclose the web along its whole width, that the surface element contacting the web is subjected to heating, and the surface element contacting the drying band is subJected to cool~ng in order to condense water evaporating from the web into the drying band, and that the drying band is separated from the dry web after they left the surface elements, and the condensed water is then removed from the drytng band.
''~ The method in accordance' w7th the invention facilltates the drying of a cardboard or a paper web by uslng the so-called suction drytng principle, the general basis of which is that the liquid or material to be dried Is In contact only with evaporating st.eam. When the pressure of the eavaporating steam is kept low by condensing the steam upon some cold surface, the evaporation takes place at a low temperature and at a low pressure. In ' sptte of the low evaporation temperature the speed of evaporat70n is very high, because the evaporating liquid botls and the heated surface can be several degrees warmer ~ 20 than the liquid itself. The temperature of the liquid thus -' reaches a value between the temperatures of the evaporating surface and the condensing surface. By passing the web to be dried and the drying band between two surface ~; elements, one of which is heated and the other is cooled, the web undergoes such a suction drying in a continuous process by causing the surface elements to run at the same speed as the web and the drying band.
Considerable advantages In suctton drying according to the tnvention are t'he htgh drying speed at a low temperature, the slmplicity of the process and the uni-, . .
formity of the process conditions.
The drying speed decreases sharply if air remains _ _ _ .
.
`` :` 1~68~103 `~
between the surface elements and in the web and/or in thedrying band. In such a case the steam evaporating from the web has to diffuse through a layer of air in order to be able to condense near the cooled surface element.
Thus, air increases the total drying resistance. For ~ -this reason, subjecting the web and the drying band to an air eliminating process before passing them~;~
between the surface elements is an essential part of the method.
The invention relates also to a drying device for applying the method in accordance with the invention.
Advantages of the drying device according to the invention are a very low purchase price and a low cost of energy consumption as well as a moderate cost of maintenance, Furthermore, the drying device is small!
noiseless and safe. The drying method in accordance with the invention does not place any restrictions on the basis weight, the speed or the quality of the web, and passing the web through the dryer as well as quality changes are easy to carry ou~. The drying of the web takes place at - ~
a low temperature so that the quality is good, and web breaks occur rarely.
As a drying band can be used a drying felt having numerous parallel flow canals passing through the felt . i!
perpendicularly to the surfaces thereof. In order to improve dewatering of the web to be dried it is ~ advantageous to use a drying band in which the part facing ;~ the web is more hydrophobic than the part facing the cooled surface element.
When the web is supported by such a drying band, ; it is easier than when using a drying felt to make sure that the surfaces of the drylng band and the cooled . . .
'' , ' ~
.
'. ' ' -'. ~, ~ ' ' . ' .' :. ' --r .
~68103 surface element, when needed, are such that the steam conden5ed thereon can be removed as easily as possible, whereby at the same time the risk decreases that the water which has evaporated from the web into the drying band would return into the web at some stage of the process.
By making the surface of the drying band facing the web more hydrophobic than the surface facing the cooled surface element the water, whlch has evaporated from the web, is prevented to pass by means of capillarity back Tnto the web even 7f the drying band would run above the web.
In addition to the advantages explained above the use of a drying wire Instead of a drylng felt ~aves both In the purchase price and in the maintenance costs due to longer wire change intervals.
The water resistance of the wire Ts accomplished by treatlng it with some suitable substance or by coating It sultably. It Ts also advantageous that the surface or the wire of the drylng band which faces the cooled surface element Is more water reslstant than satd rooled surface element. In this manner tt ts possible to obtain that elther the dryTng band or the cooled surface element retainS more water when the cooled surface element and the drying band are separated.
In the following the inventton will be described more closely with reference to the accompanytng drawing , in which Flg. 1 Is a schematic slde vtew of one embodtment of a drylng devlce for carrying out the drytng method provTded by the tnvention, Ftg. 2 ts an enlarged sectlon along line 11-11 tn Flg. 1, Fig. 3 ts an enlarged section of the edge part of the bands, and Figures 4-6 are enlarged cross sections of _ _ _ _ .;. .
.:
., . .. ~
i~68~03 embo~iments o~ a drying band havTng surface por~ions with different hydrophobic properties.
The dryer illustrated in the drawing comprises mainly two surface elements 1 an 2 formed by two endless bands, which are of nonpermeable stainless steel or other metal, rubber or plast7c. The surface elements run over ~ .
horlzontal turning rolls 3, so that between those parts of the surface elements which are position&d close to each other remalns essentlally a space with corresponds to the thickneSS of the web and the drying band. An endless drying band 4, in this case a dryTng felt, runs between - the surface elements, passes over the other turning roll 3, and returns by a route below ~he lower surface element, passTng over ordTnary guTde rolls 5. The surface elements are wTder than the web. The cardboard or paper web to be dried Ts indlcated wTth t~e reference numeral 6.
The dryer further comprTses a steam chest 7, whTch is placed above the lower run of the ~pper surface band 1 and Into whTch saturated steam (100C, 1 bar) Ts supplied from a tube 8. The chest Ts further provTded wTth condensate : collectors 9 and outlet tubes 10 for condensed water (100C).
.....
~; A shower chest 11 is posTtToned underneath the upper run of j the lower surface element 2, Tn whTch shower chest there i is a group of tubes 12 for sprayTns cooling water having a temperature of 0-20C UpOIl the lower surface of the surface element. The inlet tube for water Ts indTcat.ed wTth . 13, and the outlet tube for used cooling water is tndicated `~ with 14.
On opposlte sides of the w~b before it passes between the surface elements are located radTant heaters 15, and after the heaters a steam chest 16A into whTch superheated steam (about 120C) Ts supplTed from a tube 17, and a ;; 6 . .. ~ ..
... . , ~.. ... .... ... . .
1~68103 suction box 16B which is subjected to suction by means of a suction tube 18. For drying the drying band there are suction boxes 19.
in the described construction the dryer comprises two drying sections I and 11 in succession, between which drying sections there is a steam space 20, the top and bottom of which are covered, but the sides open. Super-heated steam (about 120C) Is supplied into the steam space - from tubes 21.
The corresponding parts of the drying section 11 are provided with the same reference numerals as in the drying secti~n 1 The drying section 11 is further provlded with an apparatus 22 for regulating the humidity proflle of the web by means of cold water, and the constructlon of the suctlon-steam box 16 differs from that of section 1.
The drylng of the web Is accomplished as follows:
The web Is passed through the radiant heaters 15, ; 20 which burn gas or use electrlcal resistances, whereby the temperature of at least the surfaces of the web rlses up to 100C. The generated steam pushes air out of the web. T;,ereafter the web and the drylng band are passed together over the suctlon box 16B, and at the same time superheated steam from the alr tlght steam box 16A Is blown through the web and the drylng band. The superheated steam pushes the remalnlng alr out of the web and the drytng band After thls the web and the drylng band are not allowed to contact alr before they enter between the . 30 surface elements 1, ~.
The leaklng of air Into the drylng band or the web from the sides of the machlne Is prevented, for Instance by suitable seals 23 at the edges of the drylng band (Flg. 3).
-, . - `~
.. .. - ~ ~
.. . ~ . . ~. . . ~ . . ..
!
_ ~ L ~
-~68103 ; The surface elements 1, 2 move at the same speed as the drying band and the web. While passtng under the steam box 7 the upper surface element 1 is heated by the action of the saturated steam which flows into the chest. The steam condenses on the surface of the upper surface element and the condensate is removed, or it drops off. The latent heat of condensation passes through the upper surface element Into the wet web. The moisture of the web evaporates at a temperature of ~0...90C, whereby the pressure (abs) of the evaporating steam is 0,20... 0,69 bar. This steam passes through the drylng band into the vicinity of the lower surface element 2. By means of cold water spraying the temperature of this surface element Ts kept at about ; lo 40C whtle passing over ~he shower chest 11. Thus the steam evaporated f!om the web condenses correspondtngly ` at a pressure (abs) of 0,01... 0,12 bar. The dryTng flux , becomes extremely hlgh, and tt Ts possTble to reach drylng values which greatly exceed the hlghest values presently achTeved.
Because the dryer consists of several dryTng .
. sections 1, Il, the web separates between the sectTons from t~e dryTng band, and Ts thus able to free Ttself of ,,;. 1 1 Its resldual stresses. Between the drylng sectlons the web ~s prevented from contact wtth aTr by means of the steam space 20. A!ternatTvely, the sheet can be passed from one drylng sectTon to the followTng completely uncovered, and ,~ the air can be removed from the web and the dryTng band sTmultaneously as they enter the second dryTng sectTon.
;
~ . The dryTng band Ts drTed by one or more of the r;~ 30 presently used methods, e.g. by passTng tt over suctlon i ,' .
. ,~ .
:. . . . ....
-: ~ ,, . ; . . ..... ... , , .: .. . . .
boxes lg, and by blowing slmultaneously superheated steam through the band. The drying band must be of a type that has numerous parallel flow canals passing through the drying band perpendicularly to the surfaces thereof, but hardly allows any gas flow in the machTne direction or the cross machine direction.
W7th this dryer tt is a very easy and safe procedure to pass the front end of the web through the dryer. A
support rope can also be used between the drying sections.
The air eliminating process and ~he drying of the drying bands causes an air-steam mixture, the temperature ; of which is about 100C. The enthalpy of this can be uttlized in the same way as the enthalpy of the humid air resulting from the hood of a normal dryer is being used at present.
Figures 4-6 711ustrate alternat7ve embodiments of a drytng band having surface portions with different hydrophobic properttes The drying band 4A, fig. 4,can consist of one paper machlne wlre, in whlch the surface 4a faclng the web 6 is more h~drophobic than the surface facing the cooled surface element. The wlre has to be of a texture fine enough not to ; leave harmful marks In the web, and thick enough to hold easlly all the water leavtng the web. The wire can be either of metal or plastlcs It Is also possible that the drylng band 4B, flg. 5, conslsts of two wlres placed one on top of the other, whereby , the wire 4c faclng the web 6 Is of flne texture and hydrophobic, and the wlre 4d faclng the cooled surface element 2 Is coarse and less hydrophoblc than the wire facing the web. The wlre 4c faclng the web has to be of ` a texture fine enough to avoid marks In the web, and the o~ther wtre 4d, whlch collects the condensate, has to be spac70us enough to receive all the water coming from the web. The wlres can be either of metal or plast1cs.
. ,.
. . . --- ~ , , : ~ . . . . ., . :.
lQ68~03 Alternatively, the drying band 4C, fig~ 6,can consist of three wires laid one on top of the other, whereby the wire 4e facing the web 6 is of fine texture, the wire 4f in the middle is hydrophobic, and the wire 4a facing the cooled surface element 2 is less hydrophobic than the wire in the middle. The wire 4e facing the web has agatn to be of a texture fine enough in order not to cause markings in the web. The wTre 4f in the middle has to be intens~vely hydrophobTc, and the wire 4g which is located most distant from the web and collects the condensate has to be less hydrophobic and spacious enough to receive easlly all the water coming from the web. The wlre 1n the middle 7s advantageously of plastics only. The two other wtres can be either of metal or plastics.
The drawing and the associated description are alnled only at 111ustrating the basic idea tnvolved with the Inventlon. The details of the embodiments for carry;ng out the method accordtng to the invention may vary considerably withln the scope o~ the claims.
, `:
: . ' ' ~ ~ .
. ' ' .: 10 - , -1 ' . .
Claims (15)
1. A method of drying a moving wet web of cardboard or paper comprising supporting said web on a moving, drying band, contacting said web with a moving, heated drying surface in order to evaporate water from said web and into said drying band, and simultaneously contacting said drying band with a moving, cooling surface to condense the water received and con-tained by said drying band, removing the condensed water from said drying band and separating a dried web of cardboard or paper from the drying band.
2. A method according to claim 1, wherein the drying surface is heated with steam at a temperature of 100° C.
under the pressure of one bar.
under the pressure of one bar.
3. A method according to claim 1, wherein the cooling surface is cooled with cold water.
4. A method according to claim 1, wherein air is removed from said web and drying band before contact with said heated drying surface.
5. A method according to claim 4, wherein air is removed from said web and drying band by heating same and blowing superheated steam through said web and drying band.
6. A method according to claim 1, wherein water is removed from said drying band by subjecting said band to suction.
7. An apparatus for drying a moving wet web of card-board or paper comprising at least one pair of surfaces formed by first and second endless, nonpermeable, movable bands capable of conducting heat, means for passing said bands in parallel over at least part of their path of movement and in the same direction on opposite sides of said web to be dried, a drying band supporting said web, said first band contacting said wet web, said second band contacting said drying band, and means for heating said first band and means for cooling said second band during parallel movement of said web and all of said bands in a forward direction.
8. An apparatus according to claim 7, wherein suction means are provided for removing water from said drying band.
9. An apparatus according to claim 7, wherein means are provided to remove air from said web and drying band be-fore said web and drying band contacts at first and second bands .
10. An apparatus according to claim 7, wherein said means for heating said first band comprises a steam box adjacent to said first band and an inlet connected thereto for supplying saturated steam into the steam box, the side of the steam box facing said first band being open.
11. An apparatus according to claim 7, wherein said means for cooling said second band comprises a shower box adjacent said second band and shower tube provided in the shower box for spraying cooling water towards said second band, the side of the shower box facing said second band being open.
12. An apparatus according to claim 7 , wherein the face of the drying band in contact with the web is more hydrophobic than the face thereof in contact with said cooling band.
13. An apparatus according to claim 12, wherein said drying band consists of one wire.
14. An apparatus according to claim 12, wherein said drying band comprises two wires positioned one on top of the other, the wire facing the web being of fine texture and hydrophobic and the wire facing the cooling band being coarse and less hydrophobic than the wire facing the web.
15. An apparatus according to claim 12, wherein said drying band comprises three wires positioned one on top of the other, the wire facing the web being of fine texture, the wire in the middle being hydrophobic, and the wire facing the cooling band being less hydrophobic than the wire in the middle.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| FI753689A FI54514C (en) | 1975-12-30 | 1975-12-30 | FOERFARANDE FOER TORKNING AV EN KARTONG- ELLER PAPPERSBANA SAMT TORKANLAEGGNING FOER TILLAEMPNING AV DETTA FOERFARANDE |
| FI761516A FI59635C (en) | 1976-05-28 | 1976-05-28 | FOERFARANDE FOER TORKNING AV EN KARTONG- PAPPERS- ELLER TEXTILBANA SAMT BANA FOER DESS TILLAEMPNING |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1068103A true CA1068103A (en) | 1979-12-18 |
Family
ID=26156774
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA267,393A Expired CA1068103A (en) | 1975-12-30 | 1976-12-08 | Method of drying a cardboard or a paper web and drying device for applying this method |
Country Status (7)
| Country | Link |
|---|---|
| US (1) | US4112586A (en) |
| JP (1) | JPS5285507A (en) |
| CA (1) | CA1068103A (en) |
| DE (1) | DE2657041C2 (en) |
| GB (1) | GB1502040A (en) |
| IT (1) | IT1065428B (en) |
| SE (2) | SE419661B (en) |
Families Citing this family (45)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FI59439C (en) * | 1980-04-25 | 1981-08-10 | Tampella Oy Ab | FOERFARANDE FOER ATT UTNYTTJANDE AV ENTALPIINNEHAOLLET I KYLVATTNET VID EN SUGTORKNINGSPROCESS FOER PAPPER CARTON ELLER EN ANNAN POROES MATTA ELLER BANA |
| FI61537C (en) * | 1981-02-19 | 1982-08-10 | Tampella Oy Ab | REFERENCE TO A CONTAINER WITHOUT CONTAINER TORKNING AV EN PAPPERS- ELLER LIKNANDE POROES BANA |
| FI66041C (en) * | 1982-04-06 | 1984-08-10 | Tampella Oy Ab | FOERFARANDE FOER TORKNING AV EN POROES BANA I EN LAONGZONSPRESS |
| FI63078C (en) * | 1982-04-06 | 1983-04-11 | Tampella Oy Ab | OVER ANCHORING FOER TORKNING AV EN PAPPERSBANA ELLER LIKNANDE |
| AU1891183A (en) * | 1982-09-09 | 1984-03-15 | Leo Capaldo | Drying paper on non porous heated belt |
| US4464844A (en) * | 1983-04-11 | 1984-08-14 | Internorth, Inc. | Method for dewatering aggregate solid substrates by miscible liquid displacement |
| US4464847A (en) * | 1983-04-11 | 1984-08-14 | Internorth, Inc. | Machine for dewatering aggregate solid substrates by miscible liquid displacement |
| SE441017B (en) * | 1984-01-19 | 1985-09-02 | Wiberg Per Arne | METHOD AND DEVICE FOR DRYING A MOISTURE FIBER COAT |
| US4631837A (en) * | 1985-05-31 | 1986-12-30 | Magoon Richard E | Method and apparatus for drying fruit pulp and the like |
| DE3705241A1 (en) * | 1986-12-24 | 1988-07-07 | Escher Wyss Gmbh | METHOD FOR MECHANICAL-THERMAL DRAINAGE OF A FIBER web |
| FI76856C (en) * | 1987-02-05 | 1988-12-12 | Tampella Oy Ab | Method and apparatus for drying a paper web or the like. |
| FI78755C (en) * | 1988-01-29 | 1989-09-11 | Tampella Oy Ab | FOERFARANDE FOER TORKNING AV EN KARTONG- ELLER PAPPERSBANA. |
| FI80101C (en) * | 1988-05-18 | 1990-04-10 | Tampella Oy Ab | ANORDINATION OF FOERFARANDE FOER TORKNING AV EN FIBERBANA. |
| FI80102C (en) * | 1988-07-01 | 1990-04-10 | Tampella Oy Ab | FOERFARANDE OCH ANORDNING FOER TORKNING AV EN FIBERBANA. |
| IT1247065B (en) * | 1991-01-10 | 1994-12-12 | Giocondo Baggio | VACUUM DRIER WITH CONTINUOUS EVAPORATION CHAMBER |
| FI92735C (en) * | 1993-02-01 | 1994-12-27 | Tampella Oy Valmet | Arrangement in a fibrous web dryer |
| FI91423C (en) * | 1993-02-01 | 1994-06-27 | Tampella Oy Valmet | Belt edge seal of the drying chamber of the dryer |
| FI92736C (en) * | 1993-02-01 | 1994-12-27 | Tampella Oy Valmet | Dryer for drying fiber web |
| FI91424C (en) * | 1993-02-01 | 1994-06-27 | Tampella Oy Valmet | Wire seal in the dryer's drying room |
| US5291666A (en) * | 1993-04-23 | 1994-03-08 | International Paper Company | Apparatus for drying roll material |
| FI943115A (en) * | 1994-06-29 | 1995-12-30 | Valmet Paper Machinery Inc | Arrangement for attenuation of sound level at the cooling layer of a cellulose dryer |
| CA2229870A1 (en) * | 1995-09-18 | 1997-03-27 | Minnesota Mining And Manufacturing Company | Coated substrate drying system |
| FR2740207B1 (en) * | 1995-10-23 | 2003-11-14 | Electricite De France | PRESSING DRYING TOOLS USING POROUS TRAYS |
| FI98080C (en) * | 1995-11-17 | 1997-04-10 | Valmet Corp | Drying device for drying the fibrous web |
| FI99269C (en) * | 1996-04-12 | 1998-02-25 | Valmet Corp | Method and arrangement for utilizing the energy of a fiber web dryer |
| FI99271C (en) * | 1996-04-12 | 1998-02-25 | Valmet Corp | Method and arrangement for utilizing the energy of a fiber web dryer |
| FI99270C (en) * | 1996-04-12 | 1998-02-25 | Valmet Corp | Method and arrangement for utilizing condensate from a fibrous web dryer |
| FI99272C (en) * | 1996-04-12 | 1998-02-25 | Valmet Corp | Method of drying a fiber web |
| DE19614887A1 (en) * | 1996-04-16 | 1997-10-23 | Voith Sulzer Papiermasch Gmbh | Machine for the production of a material web |
| FI101985B (en) * | 1996-12-10 | 1998-09-30 | Valmet Corp | Method and apparatus for drying a fibrous web |
| US6475342B1 (en) | 1996-12-10 | 2002-11-05 | Metso Paper, Inc. | Method of and arrangement for treating a fiber web |
| US5935381A (en) * | 1997-06-06 | 1999-08-10 | The Procter & Gamble Company | Differential density cellulosic structure and process for making same |
| US5938893A (en) * | 1997-08-15 | 1999-08-17 | The Procter & Gamble Company | Fibrous structure and process for making same |
| US6139686A (en) * | 1997-06-06 | 2000-10-31 | The Procter & Gamble Company | Process and apparatus for making foreshortened cellulsic structure |
| FI103681B (en) * | 1998-06-05 | 1999-08-13 | Tamfelt Oyj Abp | Arrangement for drying section of paper machine |
| FI103682B (en) * | 1998-06-05 | 1999-08-13 | Tamfelt Oyj Abp | Arrangement for drying section of paper machine |
| DE19941336A1 (en) | 1999-08-31 | 2001-03-01 | Voith Paper Patent Gmbh | Drying device |
| FI116086B (en) * | 2000-06-08 | 2005-09-15 | Avantone Oy | Check-marked paper or cardboard product and check-marked packaging |
| US6610173B1 (en) | 2000-11-03 | 2003-08-26 | Kimberly-Clark Worldwide, Inc. | Three-dimensional tissue and methods for making the same |
| EP1356150B1 (en) * | 2000-12-27 | 2006-06-14 | BSH Bosch und Siemens Hausgeräte GmbH | Method and device for dehumidifying clothes |
| US6701637B2 (en) | 2001-04-20 | 2004-03-09 | Kimberly-Clark Worldwide, Inc. | Systems for tissue dried with metal bands |
| US20070111625A1 (en) * | 2002-10-24 | 2007-05-17 | Voith Fabrics Patent Gmbh | Condensation dryer fabric |
| WO2012059619A1 (en) | 2010-11-01 | 2012-05-10 | Metso Paper, Inc. | Process for producing multilayer fiber web |
| EP2549013B1 (en) | 2011-07-21 | 2018-01-31 | Valmet Technologies, Inc. | Process and arrangement for producing a fiber web |
| WO2014018564A1 (en) | 2012-07-23 | 2014-01-30 | Zieger Claus Dieter | Multiple proportion delivery systems and methods |
Family Cites Families (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE114754C (en) * | ||||
| US2207278A (en) * | 1937-09-22 | 1940-07-09 | Joseph A Albrecht | Machine for removing surface moisture from lump material |
| DE963662C (en) * | 1953-10-07 | 1957-05-09 | Licentia Gmbh | Device for drying paper webs using a vacuum chamber |
| US3096161A (en) * | 1957-09-16 | 1963-07-02 | Owens Corning Fiberglass Corp | Heat setting of binder of fibrous masses |
| US3214330A (en) * | 1963-01-24 | 1965-10-26 | Huyck Corp | Duplex fabric paper press |
| US3214327A (en) * | 1963-04-16 | 1965-10-26 | Huyck Corp | Papermakers' felts and method for dewatering paper and similar webs |
| SE313242B (en) * | 1965-05-21 | 1969-08-04 | Karlstad Mekaniska Ab | |
| US3525160A (en) * | 1967-05-12 | 1970-08-25 | Jiri Dokoupil | Process and arrangement for drainage of wet leather and similar fibrous material |
| DE2355543B2 (en) * | 1973-11-07 | 1979-03-15 | Hoechst Ag, 6000 Frankfurt | Process for the continuous drying of textile webs |
-
1976
- 1976-12-07 GB GB51055/76A patent/GB1502040A/en not_active Expired
- 1976-12-08 CA CA267,393A patent/CA1068103A/en not_active Expired
- 1976-12-08 SE SE7613800A patent/SE419661B/en not_active IP Right Cessation
- 1976-12-09 US US05/748,736 patent/US4112586A/en not_active Expired - Lifetime
- 1976-12-16 IT IT30459/76A patent/IT1065428B/en active
- 1976-12-16 DE DE2657041A patent/DE2657041C2/en not_active Expired
- 1976-12-24 JP JP15610276A patent/JPS5285507A/en active Granted
-
1979
- 1979-02-20 SE SE7901491A patent/SE443384B/en not_active IP Right Cessation
Also Published As
| Publication number | Publication date |
|---|---|
| JPS5285507A (en) | 1977-07-15 |
| DE2657041A1 (en) | 1977-07-14 |
| SE443384B (en) | 1986-02-24 |
| US4112586A (en) | 1978-09-12 |
| DE2657041C2 (en) | 1982-05-06 |
| SE7901491L (en) | 1979-02-20 |
| SE7613800L (en) | 1977-07-01 |
| IT1065428B (en) | 1985-02-25 |
| SE419661B (en) | 1981-08-17 |
| GB1502040A (en) | 1978-02-22 |
| JPS5621879B2 (en) | 1981-05-21 |
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